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________________________________________________________________

Foot-and-Mouth Disease: Public Health Implications for Human Consumption of

Pasteurized Milk _______________________________________________________

Consultation for Dairy Management Inc. (DMI)

Provided By: University of Minnesota School of Public Health

University of Minnesota College of Veterinary Medicine, Center for Animal Health and Food Safety

David T. Harder DVM Larissa A. Minicucci DVM, MPH

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EXECUTIVE SUMMARY: Background: Foot-and-mouth disease (FMD) is a viral infection that affects cattle, swine, and other

cloven-hoofed ruminants. The United States has been free of FMD since 1929, but should

the disease be reintroduced into domestic livestock populations, serious economic

consequences could result.

Rarely will this disease infect humans, but given that some human cases have been

reported throughout history, public health implications need to be addressed.

Dairy Management Inc. requested that the University of Minnesota conduct a literature

review to assess the public health implications of human consumption of pasteurized milk

in the event of an FMD outbreak. The ensuing report is an in-depth summary of the

available scientific literature on the topic as an aid in developing risk communication

messages.

Methods:

Over 500 published papers were accessed and reviewed. Relevant information was

compiled and reported in the form of a literature review.

Findings:

FMD should be considered a rare zoonosis. The disease has been seen in humans, but its

incidence is extremely rare. Since 1921, just over 40 human cases have been reported. All

documented cases were acquired from close animal contact or through the consumption

of unpasteurized milk. There have been no human cases acquired from the consumption

of pasteurized milk or milk products.

It has been demonstrated that infected animals will shed FMD virus in the milk. Various

methods currently exist for pasteurization. Scientific studies have demonstrated that

current batch and continuous pasteurization methods will decrease and largely inactivate

the amount of virus present in milk. These processing methods will significantly reduce

the already low risk of human infection from consuming pasteurized milk. Studies

assessing Ultra High Temperature (UHT) pasteurization methods have demonstrated a

complete elimination of the virus in milk.

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Recommendations:

Based on the review of the literature contained in this report, the researchers feel

confident that the following statements/recommendations can be made:

1) FMD should not be considered a public health concern. There is virtually no risk

of infection to the general public should an outbreak occur in livestock.

2) Current pasteurization methods using minimum required temperatures and times

are sufficient to prevent human or animal infection with FMD as a result of

consuming pasteurized milk. State quarterly inspections and pasteurization

equipment checks along with dairy industry internal food safety and quality

control programs should be maintained to ensure that appropriate processes are

followed.

3) UHT methods eliminate the risk of infection, since studies have demonstrated the

complete elimination of virus in milk using this technology.

4) Compliance with World Organisation for Animal Health (OIE) and Pasteurized

Milk Ordinance (PMO) guidelines will ensure food safety in the event of an FMD

outbreak.

5) Risk communication messages may need to be designed differently based on the

stakeholders addressed. Suggested stakeholders are discussed in the review.

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INTRODUCTION:

The following report has been developed by the authors as a consultation project

for use by Dairy Management Inc. ™ (DMI). DMI has been created as a representation

of the American Dairy Association®, National Dairy Council®, and U.S. Dairy Export

Council®, to help build demand for dairy on behalf of dairy producers and is dedicated to

the success of the dairy industry. Information provided by this report will be used by

DMI to disseminate information to dairy industry communicators.

The report was written to address the following specific questions posed by DMI:

1) What is the public health risk from foot-and-mouth disease (FMD)? Is there

zoonotic potential? If there have been human cases, how did they manifest?

2) What effect does pasteurization have on FMD in milk? What are the food

safety implications?

3) What prevention strategies / recommendations can we provide to the

public?

To find answers based on scientific research, a literature review was performed to

best address each portion of the questions. The methods section of this report defines the

criteria used in the review, while the findings portion reports information accumulated

during research of the topic. A discussion of limitations experienced in the research is

followed by a conclusion of findings and recommendations for DMI.

METHODS:

Internet Reference archives:

Pubmed, a service of the US National Library of Medicine, was utilized to

perform the following keyword searches and displays the breadth of information on the

topic of FMD.

Key words All Review Foot and mouth disease 3789 207

Foot and mouth disease, humans 863 121

Foot and mouth disease, man 58 8

Foot and mouth disease,

pasteurization

5 4

Foot and mouth disease, public

health

1975 244

Foot and mouth disease, zoonosis 73 21

Foot and mouth disease, milk,

public health

42 13

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Articles listed for review were evaluated in some context ranging from abstract

review to full review. With few exceptions, non-English publications were not reviewed.

An excellent bibliography was compiled in 1965 by B. Balassa to provide

reference material for the research workers of the Plum Island Animal Disease

Laboratory. The title is Bibliography of Foot-and-Mouth Disease in Man 1695-1965, and

it lists 310 articles from the mentioned time period. Entries are arranged alphabetically

with titles of papers rendered in the languages published. An additional supplement,

Foot-and-Mouth Disease in Man A Bibliography 1966- September 1971 containing 45

more sources was provided in 1971 by R. Uskavitch. Copies of both of these sources

were found at the University of Minnesota Veterinary Medical Library and articles of

interest were located through the University of Minnesota library search engine.

Unbiased approach:

In order to preserve the academic integrity of this consult, all attempts were made

to remain non-biased and approach the research from a balanced perspective. Neither the

approach to disprove FMD as threat to humans nor the intent to prove it as a health risk

was used. A great deal of references cited in accumulated articles were also collected and

analyzed to determine the origins of information reported. This method allowed for a

greater breadth of information and understanding on the topic of FMD. It should be

noted, however, that some bias may be encountered when using the reference list of a

specific article to find more articles of interest.

FINDINGS: I. Introduction of Foot-and-Mouth Disease (FMD):

Foot-and-mouth disease (FMD) is a severe and highly contagious viral disease of

cattle and swine with reported effects also recognized in sheep, goats, deer, and other

cloven-hoofed ruminants (USDA, 2007). While some references were identified

suggesting FMD is a zoonotic disease, it is generally accepted that humans are considered

to be relatively non-susceptible to infection (Bauer, 1997). The United States has been

free of FMD since 1929, when the last of nine U.S. outbreaks was eradicated.

The disease in susceptible animals is characterized by fever and blister-like

lesions followed by erosions on the tongue and lips, in the mouth, on the teats, and

between the hooves (USDA, 2007). Most affected animals recover, but the disease

leaves them debilitated. Infection of young animals can result in death.

FMD can cause severe losses in the production of meat and milk. FMD outbreaks

not only disrupt animal trade, but also cause widespread economic and social impacts,

both in the short and long term. These include: disruption or complete blockage of raw

milk farm pick-up and delivery to dairy processing plants, as well as distribution of

finished dairy products to wholesale and retail outlets; interruption of animal feed,

veterinary pharmaceuticals and other supplies to dairy farms; and restrictions on travel /

tourism-associated industries. Furthermore, concern has been raised about potential

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terrorist organizations or rogue states that might target the $100 billion/year U.S.

livestock industry by employing the etiologic agent of FMD. Such events would garner

much media attention and could cause public concern over both the disease and food

safety.

In response to these and other concerns, President George W. Bush signed into

law the Public Health Security and Bioterrorism Preparedness and Response Act of 2002.

The purpose of this Act is stated, "To improve the ability of the United States to prevent,

prepare for, and respond to bioterrorism and other public health emergencies." (107th

congress. public health security and bioterrorism preparedness and response act of 2002.

public law 107-188.)

II. Broad Considerations for FMD:

1) Prevention and vigilance towards a FMD outbreak is crucial in today‟s society

as the majority of our nation‟s population depends on someone else to provide food for

them.

2) In the case of a biosecurity event (such as FMD), early detection would lead to

an earlier response, which, in turn, would decrease economic damage and reduce

expected volatility in agricultural industry commodity markets. Detection begins with

animal producer, veterinarian and citizen awareness, and continues with technology to

confirm any suspicions. Current monitoring systems supported by USDA that include

disease detection training will help immensely, but personnel must be trained to use

technology properly in a crisis situation.

3) Containing disease progression during an outbreak is important because the

agriculture industry must be prepared to conduct business during and after a major FMD

outbreak. Agricultural industry leaders, as well as the appropriate federal government

agencies, must be properly trained to react in a crisis situation.

4) At all levels, a coordinated communication strategy must include the

development of effective messages for government and industry groups that use risk

management strategies in risk communication to the general population.

In the event of an outbreak of FMD, consumer confidence in the food supply may

be undermined by the public‟s perception that animal products might contain the virus,

though not harmful to humans. Consumers may question the safety of all animal products

(e.g., milk) on store shelves even those produced with pasteurized milk (Tomasula et al.,

2007).

III. Causative Agent:

FMD is caused by a picornavirus; other members of this family of viruses include

the swine vesicular disease virus, the human hepatitis A virus, and rhinoviruses.

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Picornaviruses are 22 to 30 nanometers (nm) in diameter, naked (unenveloped), and

display an icosahedral shape. The FMD virus belongs to the genus aphthovirus. The virus

is a positive sense, single-stranded RNA virus. There are 7 immunologically distinct

serotypes of FMD virus: FMDV-A, FMDV-O, FMDV-C, FMDV-ASIA1, FMDV-SAT1,

FMDV-SAT2, and FMDV-SAT3. Also, more than 60 subtypes of the virus exist

(AVMA, 2008).

Most picornavirus species are host-specific and are highly resistant to many

disinfectants. The FMD virus is inactivated by sodium hydroxide (2%), sodium carbonate

(4%), and citric acid (0.2%). Resistance has been noted in iodophores, quaternary

ammonium compounds, hypochlorite and phenol, especially when organic matter is

present (OIE - World Organisation for Animal Health, 2002).

IV. Significance to Public Health:

Due to media coverage of zoonotic diseases, such as bovine spongiform

encephalopathy (BSE), tuberculosis, and E. coli 0157, public concern has been raised to

the potential risks of contracting FMD from livestock sources. FMD infections in humans

are very rare, with just over 40 cases (confirmed by virus isolation, or rise in antibody

titers, or both) diagnosed since 1921. With this very low number of documented human

cases, FMD is considered an unlikely zoonosis. In humans, vesicular lesions can be seen,

but the signs are generally mild, and human patients usually recover a week after the last

blister formation. FMD is not considered to be a direct public health threat, as it crosses

the species barrier into humans with great difficulty and with little effect. Given the high

incidence of the disease in animals, both in the past and in more recent outbreaks

worldwide, its comparable occurrence in humans is very rare. (Prempeh, Smith, &

Muller, 2001)

During the second half of the 19th

century, many authors recorded cases of

aphthous* diseases in man which appeared to have been acquired from animals affected

by FMD (Hyslop, 1973). In one report, consumption of infected (raw) milk appeared to

be the primary factor associated in 22 cases of human infection. This same author

mentions that the authenticity of early documented cases is often a matter of speculation

since coincidental appearances by diseases that appear similar in humans can occur

during animal FMD outbreaks.

The circumstances in which FMD does occur in humans are not well defined;

however, all reported cases have had close contact with infected animals. There is one

report from 1834 of three veterinarians acquiring the disease and displaying clinical

manifestations from deliberately drinking 250 ml of raw milk from infected cows for

three consecutive days. However, reports documented before 1897, when Loeffler and

Frosh discovered the virus for FMD, were not confirmed as FMD either by isolation of

the virus or identifying immunoglobulins after infection (Bauer, 1997).

A well-documented human case of FMD in the United Kingdom occurred in 1967

during an outbreak. The farm worker affected was thought to have contracted FMD by

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drinking virus-contaminated milk supplied by an infected cow on the farm (Mayor,

2001). Symptoms of the affected man included mild fever, sore throat, blisters on his

hands, and wheals on his tongue. The patient described the lesions as uncomfortable and

tingling, and his tongue as hot, tingling and sore. Traces of type O FMD were found in

one tissue sample, but not in others, so speculation was that the man may also have been

suffering from a skin condition of unknown origin. The man recovered within a few

weeks and had no lasting health effects (Armstrong, Davie, & Hedger, 1967).

Table 1 is a representation of some of the documented human cases of FMD and

virus type isolated (Berrios, 2007). Type O FMD is commonly referenced in these

articles and exposure to virus from drinking raw milk is documented.

Table 1. Articles on FMDV in Humans.

(Translation from article written in Spanish) (Berrios, 2007)

Year Author Virus

type

Country Infection source

1929 Trautwein A Germany Work related

1934 Von Scheltz O Germany ?

1938 Rinjard O France milking

1938 Magnusson O Sweden Ill animal

1938 Flaum O Sweden milking

1941 Stenstrom O Sweden milking

1950 Holm O The Netherlands ?

1951 Wahl C Germany milking

1954 Czarnowski C Poland ?

1955 Geiger C Germany laboratory accident

1959 Garbe C Germany laboratory accident

1960 O Chile laboratory accident

1962 Pilz C Germany laboratory accident

1962 Pilz O Germany laboratory accident

1963 Schwann C Poland milking

1964 Heinig C Germany ?

1964 Kobuclewitcz C Poland raw milk ingestion

1965 Pilz O Germany laboratory accident

1967 Salazhov A Russia Milking/raw milk drank

1967 Elssner C Germany Collecting environmental

samples

1967 Armstrong O England Ill animal

2001* Bohn* O* England* Ill animal*

*No literature found for the reference. (Mayor, 2001) reports that the last

documented case in the U.K. was in 1967.

The virus type most often isolated in humans with FMD is type O followed by

type C and rarely A. The incubation period in humans ranges from 2-6 days. Symptoms

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displayed have mostly been mild and self limiting, mainly uncomfortable tingling blisters

on the hands but also fever, sore throat, and blisters developing on the feet, in the mouth,

as well as on the tongue. (Bauer, 1997)

Apthae*forming in humans from FMD, range in size from that of a pin head to as

large as 2 cm in diameter. Initially blisters are clear and yellowish in color, but soon

become thickened. These blisters then dry up within two to three days and the skin is

sloughed off showing the red basal epidermal layer. With care, the areas heal quickly by

the body‟s normal methods. Secondary blisters then may appear up to five days after

development of primary blisters. Recovery is usually well advanced within a week after

the last blister appears (Bauer, 1997).

Several other human diseases are characterized by formation of skin vesicles and

clinical symptoms similar to FMD. Manifestation of the clinical signs associated with

FMD in humans must be differentiated from the diseases listed in Table 2. Historically, in

the event of a livestock FMD outbreak, coincidental appearances of the listed diseases

can be misinterpreted by the general public as human FMD (Hyslop, 1973).

* An aphthous is defined as a small sensitive painful ulcer crater in the lining of the mouth and is more

commonly called a canker sore. Aphthous ulcers are one of the most common problems that occur in the

mouth. About 20% of the population (1 in 5 people) has aphthous ulcers at any given time. These ulcers

typically last for 10-14 days and they heal without leaving a scar. There are many possible causes of

aphthous ulcers and often the cause is unknown (Ulcer, aphthous definition - medical dictionary definitions of

popular medical terms easily defined on MedTerms.)

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Table 2. Differential diagnosis between foot and mouth disease and other

viral diseases with similar clinical characteristics (Lopez-Sanchez, Guijarro Guijarro,

& Hernandez Vallejo, 2003).

Disease Agent Reservoir Oral Manifestations Systemic Manifestations

Foot and Mouth

Disease

Picornavirus

(RNA):

Aphthovirus

Cleft hoof

herbivores

.

Vesicles

throughout

the oral

mucosa.

Dysphagia

Fever

Malaise

Muscle pain

Diarrhea

Vesicles

affecting

nasal mucosa

and hands

Vesicular

stomatitis

Rhabdovirus

(RNA):

Vesiculovirus

Cleft hoof

herbivores

and equine

species

Vesicles

throughout

the oral and

tonsillar

mucosa.

Dysphagia.

Fever

Malaise

Adenopathies

Hand, foot

and mouth

disease

Picornavirus

(RNA):

Enterovirus:

Coxsackie,

Echo

Humans Vesicles

throughout

the oral

mucosa.

Dysphagia.

Vesicles

affecting

hands and

feet

Herpangina

Picornavirus

(RNA):

Coxsackie

Humans Vesicles

affecting the

uvula, soft

palate and

tonsils.

Dysphagia.

Fever

Vomiting

Abdominal

pain

Primary

herpetic

gingivostomatitis

Herpes virus

(DNA):

Herpes virus

hominis 1

and 2

Humans Vesicles

throughout

the oral

mucosa.

Dysphagia.

Fever

Malaise

Joint pain

Adenopathies

Another significant factor associated with an outbreak of FMD involves the

psychosocial effects to the human population involved. Research in the United Kingdom

was conducted to understand the health and social consequences of the 2001 FMD

epidemic for a rural population in the most heavily affected North Cumbria region.

Respondents' reports showed that life after the epidemic was accompanied by distress,

feelings of bereavement, fear of a new disaster, loss of trust in authority and systems of

control, and the undermining of the value of local knowledge. Distress was experienced

across diverse groups well beyond the farming community (Mort, Convery, Baxter, &

Bailey, 2005).

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Key Points:

FMD rarely occurs in humans and disease manifestation (often mild and self-limiting) is

most often associated with either consumption of unpasteurized milk or close contact with

infected animals. Based on the published scientific literature, no human cases of FMD

have been reported following consumption of pasteurized milk or milk products.

V. Disease in Animals:

Although pigs are major producers of virus aerosols, cattle produce several

magnitudes more of the virus in the epithelium of the tongue, which often sloughs off and

is shed during clinical disease, as well as in saliva. The virus is also shed in urine, feces

and milk. The 10–30 g of tongue blister epithelium, which a cow with FMD can

discharge, may represent not less than one billion infectious units (IU).These enormous

quantities of shed virus can contaminate the environment (boots, clothes, tires etc.) and,

therefore, cattle are considered the main source of environmental contamination. FMD

infection can be spread by an airborne route through the upper and lower respiratory

tract, although it can also enter the new host through abrasions of the oral epithelium,

hooves, and mammary tissue.

The peak of infectivity is just prior to or during the development of lesions. It is

then greatly reduced 3–4 days after the lesions develop. Some virus strains are host

adapted (Sutmoller, Barteling, Olascoaga, & Sumption, 2003).

Clinical Signs:

The clinical manifestations of FMD in animals usually are severe, and sequelae

following initial recovery can seriously impair livestock productivity (Sutmoller et al.,

2003).

The clinically visible lesions include rapidly rupturing vesicles filled with clear,

straw-colored fluid. Vesicles vary in size from 0.5-10 cm in diameter and appear in areas

subjected to pressure, irritation, or friction, on either skin or mucosal surfaces. These

areas include interdigital spaces, heels, coronary bands, teats, oral mucosa, nostrils and

rumen pillars. Ruptured vesicles may leave erosions or ulcerations, but begin as small

blanched areas of epithelium that rapidly fill with fluid and eventually rupture.

Epithelium will separate and slough leaving raw ulcers, tags of epithelial tissue, or

erosions. These areas heal rapidly and leave discolored areas that fade until completely

healed. Death is uncommon except in bovine neonates where cardiac and skeletal muscle

necrosis may be evidenced upon necropsy (Kahrs, 2001).

Prolonged healing can cause marked weight loss and decreases in milk and meat

production. Anorexia is caused by painful oral lesions, and lameness is due to painful

digits. Commonly, animals will exhibit shifting of weight on feet, and secondary bacterial

infections of the hooves frequently arise. Painful teat lesions may prevent nursing or

milking. Mastitis of primary viral or secondary bacterial origin is a common effect

(Kahrs, 2001).

FMD is clinically indistinguishable from vesicular stomatitis, and vesicle

formation is preceded by a viremic stage consisting of fever, depression, anorexia,

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listlessness, and occasional shivering. As vesicles form, animals display excess

salivation, nasal discharge and classically in cattle, lip smacking (Kahrs, 2001).

Viral Transmission in Milk:

FMD virus is shed into the milk, blood, pharynx, rectum and vagina, before onset

of clinical manifestations in infected cows. The virus can appear in the milk of animals

exposed to it through contact with infected animals several days before clinical signs of

the disease appear (Burrows, 1968). Experiments in which the bovine udder was

inoculated with FMD virus showed that it is highly capable of producing large amounts

of the virus (Burrows, Mann, Greig, Chapman, & Goodridge, 1971).

Information regarding the amount of FMD virus required to infect animals

through various routes, including ingestion, has been compiled (Sellers, 1971). From

previous data, it was determined that the amount of virus in infected milk may be up to

105.5

ID50†

per ml. Only 1 mL at a concentration of 105

ID50 per ml would be needed to

infect a pig through ingestion. A normal daily intake of 0.5L of milk would be sufficient

to initiate infection in a pig if the concentration were 102.3

ID50 per ml. Calves consuming

normal daily milk amounts at 0.5-9L, would need virus concentrations in the range from

103.3

– 10 2.05

ID50 per ml.

Key Points:

In order to ascertain if animals are affected by FMD, it is important to

understand what clinical manifestations would be observed. Confirmation of an outbreak

in animals would trigger appropriate risk communication messages to producers and

processors to provide tools to address the spread of the disease and for consumers to

assure them of the safety of the food supply. As virus can be excreted in milk prior to an

animal demonstrating clinical signs, producers must be able to account for animals and

products in the food chain once the disease is identified.

VI. Pasteurization / Food Safety:

“The terms "pasteurization", "pasteurized" and similar terms shall mean the process of

heating every particle of milk or milk product, in properly designed and operated

equipment, to one (1) of the temperatures given in the following chart and held

continuously at or above that temperature for at least the corresponding specified time.”

† ID50 (infectious dose) is the virus titer that will cause infection in 50% of individuals

exposed.

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Table 3. Pasteurized Milk Ordinance (PMO) Temperature and Time Standards for

Pasteurization

Temperature Time

63ºC (145ºF)* 30 minutes

72ºC (161ºF)* 15 seconds

89ºC (191ºF) 1.0 second

90ºC (194ºF) 0.5 seconds

94ºC (201ºF) 0.1 seconds

96ºC (204ºF) 0.05 seconds

100ºC (212ºF) 0.01 seconds

*If the fat content of the milk product is ten percent (10%) or greater, or if the milk

contains a total solids of 18% or greater, or if it contains added sweeteners, or if it is

concentrated (condensed), the specified temperature shall be increased by 3ºC (5ºF).

(Section 1. FF of PMO, 2007)

Pasteurization Methods

There are two basic pasteurization methods

1) Batch Method

2) Continuous Method (usually high temperature, short time (HTST))

Batch Method

The batch method (Figure 1) uses a vat pasteurizer, consisting of a vat surrounded

by a jacket using a heating medium such as circulating water, steam or heating coils of

water or steam. In the vat, the milk is heated and held throughout the holding period

while being agitated. The milk may be cooled in the vat or removed hot after the holding

time is completed for every particle. Some modifications include that the milk may be

partially heated in a tubular or plate heater before entering the vat (Goff, 2007). However,

the times identified above have to be met while the milk is in the vat.

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Figure 1: (Goff, 2007)

Continuous Method

For most continuous processing, a high temperature short time (HTST)

pasteurizer is utilized. The continuous process method has a few advantages over the vat

method, the most important being time and energy saving. The actual heat treatment is

accomplished using a plate heat exchanger, which consists of a stack of corrugated

stainless steel plates clamped together in a frame (Figure 2). There are several flow

patterns which can be used. Gaskets are placed to define the boundaries of the channels

as well as to prevent leakage. The medium used for heating can be either vacuum steam

or hot water (Goff, 2007)

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Figure 2: Schematic diagram of a plate heat exchanger (Goff, 2007)

HTST Milk Flow Overview “Cold raw milk at 4° C in a constant level tank is drawn

into the regenerator section of pasteurizer. Here it is

warmed to approximately 57° C - 68° C by heat given

up by hot pasteurized milk flowing in a counter current

direction on the opposite side of thin, stainless steel

plates. The raw milk, still under suction, passes through

a positive displacement timing pump which delivers it

under positive pressure through the rest of the HTST

system.

The raw milk is forced through the heater

section where hot water on opposite sides of the plates

heat milk to a temperature of at least 72° C. The milk,

at pasteurization temperature and under pressure, flows

through the holding tube where it is held for at least 16

sec. The maximum velocity is governed by the speed of

the timing pump, diameter and length of the holding

tube, and surface friction. After passing temperature

sensors of an indicating thermometer and a recorder-

controller at the end of the holding tube, milk passes

into the flow diversion device (FDD). The FDD

assumes a forward-flow position if the milk passes the

recorder-controller at the preset cut-in temperature

(>72° C). The FDD remains in

normal position which is in diverted-

flow if milk has not achieved preset

cut-in temperature. The improperly

heated milk flows through the

diverted flow line of the FDD back

to the raw milk constant level tank.

Properly heated milk flows through the forward

flow part of the FDD to the pasteurized milk

regenerator section where it gives up heat to the raw

product and in turn is cooled to approximately 32°

C - 9° C.

The warm milk passes through the cooling section

where it is cooled to 4° C or below by coolant on

the opposite sides of the thin, stainless steel plates.

The cold, pasteurized milk passes through a vacuum breaker at least 12 inches above the highest raw milk

in the HTST system then on to a storage tank filler for packaging.” (Goff, 2007)

HTST pasteurization is important to the dairy industry because of the operating

efficiencies that it affords. Properly operated, these units allow a high volume of

production in a minimum of processing space. The ability of HTST pasteurizers to assure

a safe, finished milk or milk product hinges on the reliability of the time-temperature-

pressure relationships that must prevail whenever the system is in operation (PMO,

2007).

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HTST heating is the most commonly utilized method of pasteurization for fluid

milk today. Milk is usually heated in a plate heat exchanger to a specified temperature

followed by holding at that temperature in a pipe for a specified period of time (Tomasula

& Konstance, 2004). Current Pasteurized Milk Ordinance (PMO, 2007) standards for

HTST heating of milk require heating to a minimum of 72°C and a holding time of at

least 15 seconds as seen in Table 1.

Additionally, higher temperatures are used in the following methods:

- Ultra-Pasteurization

- Ultra High Temperature/ Aseptic Processing

Ultra-Pasteurization (UP): The term “Ultra-Pasteurization”, when used to describe a dairy

product, infers that such products shall have been thermally processed at or above 138°C

(280°F) for at least two (2) seconds, either before or after packaging, so as to produce a

product, which has an extended shelf-life under refrigerated conditions (PMO, 2007).

Ultra High Temperature (UHT), or Aseptic Processing: The term “Aseptic Processing”,

when used to describe a milk product, infers that the product has been subjected to

sufficient heat processing and packaged in a hermetically sealed container (PMO, 2007).

The product is termed "shelf stable" and does not need refrigeration until it is opened.

FMD research regarding pasteurization methods:

A study was performed to determine whether continuous flow HTST

pasteurization would be more effective than batch pasteurization methods in eliminating

or reducing the infectivity of FMD in naturally infected milk. It also aimed to determine

the temperature-time conditions, at temperatures <100° C, required for eliminating the

virus in whole milk and 2% milk under flow conditions (Tomasula et al., 2007).

Specifically, the study aimed to determine whether HTST pasteurization

simulating that of commercial operations would be effective in eliminating FMD from

naturally infected whole and 2% milk. The study concluded that HTST pasteurization is

more efficient than batch pasteurization methods in eliminating the FMD virus in whole

and skim milk (Tomasula et al., 2007). The results of this study largely agree with those

of (Hyde, Blackwell, & Callis, 1975) and (Blackwell & Hyde, 1976), who used the batch

processing techniques to simulate HTST pasteurization of milk.

The above described studies indicate that the FMD virus encapsulated by milk fat

has increased heat resistance. Modern milk-processing plants with efficient skimming

operations and homogenization as part of pasteurization may release the residual

encapsulated virus, ensuring its destruction during pasteurization, or may reduce residual

virus to much lower levels than observed in this and previous laboratory- scale studies

(Tomasula et al., 2007). Milk fat will be discussed in more detail later.

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Residual Virus:

A series of pasteurization experiments using FMD were performed by researchers

at the Plum Island Animal Disease Center at Orient Point, New York (Blackwell & Hyde,

1976; Hyde et al., 1975). HTST pasteurization was simulated using a batch type

experimental model that heated milk to 72° C for a holding time of 15 seconds, which

meets criteria of the 2007 regulations for time and temperature requirements of the

Pasteurized Milk Ordinance (PMO, 2007). A 6 log10 reduction in FMD was noted,

however, inoculation of the pasteurized sample into steers demonstrated residual

infectivity.

Steer inoculation has been deemed the most sensitive method to detect infectious

FMD in naïve (previously unexposed) animals (Tomasula et al., 2007). Other methods

that detect viral antigens (ELISA) or viral RNA (real time reverse-transcription PCR)

exist, but fail to distinguish inactivated from infectious‡ virus.

When the pasteurization time for whole milk was increased to 2 minutes at 72° C,

steers inoculated with the milk developed FMD, but under identical conditions using

skim milk, 1 of 3 steers inoculated with pasteurized skim milk samples developed FMD.

When skim milk was heated at 72° C for 2 minutes, followed by evaporation of the initial

volume by 50% at 65° C for 1 hour, the virus was eliminated. Whole milk samples

pasteurized at 85° C for 15 seconds were infectious to steers, but under identical

conditions using skim milk, only 1 of 5 steers inoculated with pasteurized skim milk

samples developed FMD (Blackwell & Hyde, 1976).

In review of the these studies, increases in pasteurization temperature or holding

time do not completely eliminate the virus in whole milk, but are effective in reducing,

and in some cases eliminating, the virus in skim milk (Tomasula et al., 2007).

Conclusions of (Blackwell & Hyde, 1976; Hyde et al., 1975) suggested that since FMD

survives the evaporation of whole milk heated for expanded exposure periods but not that

of skim milk receiving the same treatment; butterfat in cream of whole milk confers an

even higher degree of protectivity during heating than the protein in skim milk.

It should be noted, however, that even though residual infectivity was observed

with relatively large volumes of milk [(2 ml) directly inoculated intradermally (20 sites

on tongue) and intramuscularly (4 sites in gluteals) into steers], the ability of this milk to

infect by oral or other routes is unlikely (Tomasula et al., 2007).

‡ Inactivated virus are unable to produce evidence of growth or cause damaging

effect on tissues but still cause antibody production. An infectious virus is able to cause

infection, growth and damaging effect to tissues.

18

Homogenization:

Modern processing plants homogenize and clarify (remove solid impurities from

milk) prior to heating, which helps break down the milk fat globules and removes debris.

This process may be of benefit in exposing FMD virus encapsulated in milk fat and cells,

which is then either destroyed by heat or removed in association with debris (Tomasula &

Konstance, 2004).

Homogenization is defined as the mechanical treatment of the fat globules in milk

brought about by passing milk under high pressure through a small orifice. This results in

a decrease in the average diameter and an increase in number and surface area, of the fat

globules (Goff, 2007). As mentioned above, this process allows better access to virus

encapsulated in the milk fat.

Milk pH:

Milk pH is an important variable that allows the virus to become more stable as

the value rises. Cows infected with FMD tended to have a more alkaline milk output

(Tomasula et al., 2007) where FMD infected milk had a pH of 7.1 compared to 6.7 prior

to infection. Similar results were reported previously (Hyde et al., 1975). Earlier studies

of the virus found it most stable at a pH between 7 and 7.5 and the time to reduce viral

titers was decreased if pH was 6.7 as opposed to 7.6 (Tomasula et al., 2007).

Dilution effects:

An important variable not represented in the studies conducted by (Blackwell &

Hyde, 1976; Hyde et al., 1975; Tomasula et al., 2007) is that commercial milk and milk

product-processing operations blend massive quantities of milk from various dairy farms.

In an FMD outbreak event, milk tankers arriving at a plant, with products from farms

with cows not yet exhibiting clinical signs, would be mixed in holding tanks with milk

from non-infected farms. The blending of infected and non-infected milk would display a

dilution effect of virus particles and lower the pH of the bulk quantity. Milk

pasteurization was demonstrated to be much more effective in virus inactivation when pH

of milk is closer to the normal (uninfected by FMD) levels of 6.7 (Tomasula et al., 2007).

It was estimated that if 10% of a lactating dairy herd became infected, the

produced infected milk would be diluted in the farm bulk tank by a 10-fold dilution

(Donaldson, 1997). The milk truck tank would further dilute (5-fold dilution), followed

by further mixing in the processing plant, removal of coarse particles by filtration (10-

fold reduction in virus), and followed by HTST pasteurization (71.7°C, 15 s) which

would produce a 105 reduction in virus. This would result in a virus concentration of

101.9

–102.9

ID50/l. It was further estimated that for a single calf to have a high probability

of obtaining an infectious dose from pasteurized milk, 1,250–12,500L (330-3302 gallons)

would need to be consumed. A single pig would need to consume 125-250L (33-66

gallons) for an infective dose (Donaldson, 1997). Calves normally consume 0.5-9L and

pigs consume 0.5-4.1L of milk daily (Sellers, 1971). If a calf inhaled some of the milk as

19

it was drinking, the likelihood of infection would be increased as a much lower infectious

dose is required to infect cattle by the respiratory route as compared to the oral route.

Key Points:

After dilution factors and pasteurization have been accounted for, scientific

studies have shown that cattle and swine consuming pasteurized milk are highly unlikely

to contract an infection since it is physically impossible to ingest the liquid amount

calculated to infect the animals. This result could plausibly be extrapolated to humans,

although there have been no studies specifically looking at infectivity in humans.

Particular attention should be paid to time, temperature, homogenization, and pH during

processing to further ensure a decreased risk of infection from pasteurized milk

consumption.

Other Dairy products:

A review of animal products and the effect of processing to reduce FMD titers has

been written (Ryan, Mackay, & Donaldson, 2008). The results are described and

referenced below:

Milk powder: Milk and skimmed milk used to produce milk powder are heated to

80–90°C for 30 s, which produces a 105.4

–106

ID50 decrease in infectivity. Subsequent

roller- or spray-drying should further inactivate any residual virus.

Cream: Cream has a higher concentration of fat globules than milk. FMD virus

survived in cream heated at 93°C for 16 s, with up to 104.5

pfu/ml detected in cell culture

after this treatment. This temperature is higher than commercial cream pasteurization.

Cheese: Virus survival is dependant on the manufacturing conditions and pH of

the cheese concerned, and so the data for one cheese cannot be extrapolated to another.

See Table 4 for results.

Yogurt: No data is available on FMD virus survival but it is speculated that the

low pH involved in manufacturing should inactivate the virus.

Table 4. Detection of Viruses in Dairy Sources (Ryan et al., 2008)

Product

Amount of virus present or longest

detection time References

During

processing

After

processing/storage

Unpasteurized

bottled milk 10

4.0 MID50/ml

Hedger and Dawson

(1970)

Milk (65°C, 64-min

pasteurization)

Virus detected by

cattle inoculation (CI) Hyde et al. (1975)

20

Milk (HTST

pasteurization) 10

3.0 pfu/ml Hyde et al. (1975)

Milk (UHT

pasteurization) Virus not detected Cunliffe et al. (1979)

Milk powder* Decrease in infectivity

of 105.4

–106.0

ID50

Donaldson (1997),

Bekkum and Leeuw

(1978)

Cream (93°C, 16 s)† 10

4.5 pfu/ml Blackwell (1978a)

Butter‡ Detected by CI at 30 days Blackwell (1978a)

Butter oil‡ Detected by CI at 45 days Blackwell (1978a)

Cheddar cheese

(raw milk)§

Detected by CI at 60 days Blackwell (1976)

Cheddar cheese

(heated milk, 67°C,

60 s)§

Detected by CI after

preparation, before

curing

Blackwell (1976)

Camembert cheese

(pasteurized milk,

72°C for 16 s)¶

Detected by CI at 21 days Blackwell (1976)

Mozzarella cheese

(pasteurized

milk, 72°C for 16 s)

Virus not detected Blackwell (1976)

Emmentaler cheese

(raw milk)**

Virus detected

during manufacturing,

not detected during

curing

Kihm et al. (1979)

Sweet whey Detected by CI Blackwell (1978b)

Acid whey Virus not detected Blackwell (1978b)

Lactose, α- and β-

lactalbumin Virus not detected Blackwell (1978b)

Casein from HTST

milk Virus detected by CI

Cunliffe and Blackwell

(1977)

*Milk and skimmed milk used to produce milk powder is heated to 80–90°C for 30 s then roller- or spray-dried (Bekkum and Leeuw, 1978; Donaldson, 1997).

†Cream was heated for 16 s at 93°C after storage for 18 h at 4°C (Blackwell, 1978a).

‡Butter was made from cream heated for 16 s at 93°C. The pH of these samples was 5.4 (Blackwell, 1978a).

21

§Virus was detected in cheddar cheese made from raw milk after 60 days of curing but not

120 days. This is in excess of the minimum curing time for this cheese. Virus was detected in cheese made from heated milk (67°C for 60 s) after preparation but not after 30 days of curing (Blackwell, 1976).

¶Virus was detected in cheese made from pasteurized (72°C for 16 s) milk after 21 days of curing but not 35 days. Twenty-one days is the normal curing time (Blackwell, 1976).

**The cheese is stored after manufacturing for at least 4 months at pH 5–5.6 (Kihm et al., 1979).

Extended form of resources used in Table 4 are located in Appendix A for use as

reference.

(Ryan et al., 2008) _______________________________________________________________________________

Strategies and Recommendations for Milk Processing:

HTST

United States processing plants typically use HTST pasteurization to process milk

at temperatures ranging from 72° C to 81° C, with holding times consistent with the

Pasteurized Milk Ordinance (see Table 1) and including time ranges up to 40 seconds.

This is consistent with recommendations discussed below for inactivating FMD in the

event of an outbreak.

UHT

In the United States, ultrapasteurized milk, sold in aseptic packages, is processed

at temperatures that range from 137 -143° C with holding times of 2 to 3 seconds. This

process results in complete destruction of FMD virus in both whole and skim milk

(Walker, de Leeuw, Callis, & van Bekkum, 1984).

The current International Animal Health Code recommendations issued by the

World Organisation for Animal Health (OIE) to inactivate FMD in the event of an

outbreak are as follows:

Milk and cream for human consumption:

For the inactivation of viruses present in milk and cream for human consumption, one of

the following procedures should be used:

1) A sterilization process applying a minimum temperature of 132°C for at

least one second (ultra-high temperature [UHT]), or

2) If the milk has a pH less than 7.0, a sterilization process applying a

minimum temperature of 72°C for at least 15 seconds (high temperature -

short time pasteurization [HTST]), or

22

3) If the milk has a pH of 7.0 or over, the HTST process applied twice.

Article 3.6.2.6.(Terrestrial animal health code - 2007)

These recommendations are based on findings of the scientific community to reduce

FMD in milk.

Double HTST pasteurization could be implemented most efficiently by increasing

the pasteurization temperature. In the event of an outbreak, however, it is unlikely that

milk in the bulk tank would exceed a pH of 7 due to dilutional effects (Tomasula et al.,

2007).

Milk for animal consumption:

For the inactivation of viruses present in milk for animal consumption, one of the

following procedures should be used:

1) The HTST process applied twice, or

2) HTST combined with another physical treatment, e.g. maintaining a pH of

6 for at least one hour or additional heating to at least 72°C combined with

desiccation, or

3) UHT combined with another physical treatment referred to in point 2

above.

Article 3.6.2.7.(Terrestrial animal health code - 2007.)

Lowering the pH of milk to 6 for one hour after HTST pasteurization is difficult

to implement practically, however (Tomasula et al., 2007).

DISCUSSION:

The intent of this consultation was to explore public health risks associated with

FMD, zoonotic potential of the virus, review documented human manifestations of

disease, and discuss the effects of pasteurization on the virus. With the information

addressing the mentioned queries, prevention strategies and recommendations can be

made by Dairy Management Inc. (DMI) to address to the public.

Limitations experienced by the author in compiling an extensive database of

historical research on FMD include that much of the information is accessible only in the

original published language. Many articles are published in European languages other

than English, making access to the entire FMD research database impossible for those

(author of this document included) limited by language barriers. Information displayed in

Table 1 regarding human FMD cases, type, and exposure sources was translated from an

23

article originally written in Spanish through the help of Dr. Alfonso Lago from the

University of Minnesota, College of Veterinary Medicine.

A significant amount of English literature on FMD was compiled for this

document and cross referencing was made available through internet research journal

databases. Articles not available via the internet were located through the extensive

University of Minnesota Library System.

CONCLUSIONS AND RECOMMENDATIONS:

It is of considerable epidemiological importance that FMD can be excreted in the

milk of cattle, and most likely other milking animals such as goats and sheep, for several

days before the clinical signs of disease become apparent. Once the disease has been

recognized in a herd, however, the implementation of control measures and biosecurity

„codes of practice‟ for treating milk that is potentially infected should prevent further

spread by that means (Donaldson, 1997).

Control measures including feeding animals only pasteurized milk, and careful

handling of raw milk on the farm, in the milking parlor, at the bulk tank, and in transport

(pick up and delivery) to the processing plant are paramount to prevent spread of FMD

among animals and farms in the event of an outbreak.

As discussed, there are studies that demonstrate methods to reduce or eliminate

FMD in milk and milk products. These studies provide adequate guidelines for

appropriate milk and milk product processing to ensure food safety. Unfortunately, there

are no published studies that fully quantify d- and z-values for FMD in food products.

The d-value (decimal reduction time) is a measure of the heat sensitivity of a virus;

defined as the length of time it takes for the quantity to decrease 10-fold at a given

temperature. From measuring d-values at different temperatures, the thermal death time,

which is the time it takes for virus levels to reach 100 at a given temperature, can be

calculated. The z-value is the temperature increase necessary to decrease the thermal

death time 10-fold (Ryan et al., 2008). One study measured a thermal death time curve in

milk derived from FMD-infected cows through plotting virus inactivation points against

temperature and time (Walker et al., 1984), but further research to establish these

parameters for FMD in a greater range of products would be very useful. This would

enable a more accurate risk assessment posed by certain products (Ryan et al., 2008).

Overall Recommendation:

Although there are scientifically authenticated reports of human FMD infections,

humans are generally considered to be non-susceptible to infection by the virus. If

recommendations of the OIE and PMO are followed in processing and milk handling,

DMI can relay the message that milk consumption is not a public health threat.

Significant research accumulated by the scientific community and discussed in this

document supports this statement on transmission and risk of exposure.

24

Key Points:

- Humans are generally considered to be non-susceptible to infection by FMD,

rendering the disease an unlikely zoonosis.

- Humans have contracted the disease from close contact with animals, exposure to

environments containing the virus, and drinking unpasteurized milk.

- Humans do not contract the disease from drinking pasteurized milk. No cases

have been documented.

- In the event of a FMD outbreak, milk pasteurized in accordance with the

Pasteurized Milk Ordinance is safe for human consumption. The process

inactivates and can destroy the FMD virus. The current International Animal

Health Code recommendations issued by the World Organisation for Animal

Health (OIE) to inactivate FMD in the event of an outbreak should be utilized.

- It is recommended that individuals not drink unpasteurized milk from any animal,

whether FMD infected or not, since the risk of infection by pathogens other than

FMD remains.

25

References

107th congress. public health security and bioterrorism preparedness and response act of

2002. public law 107-188. Retrieved 6/16/2008, 2008, from

http://www.fda.gov/oc/bioterrorism/PL107-188.html

American Veterinary Medical Association. Foot and mouth disease backgrounder.

Retrieved 5/23/2008, 2008, from http://www.avma.org/public_health/fmd_bgnd.asp

Armstrong, R., Davie, J., & Hedger, R. S. (1967). Foot-and-mouth disease in man. British

Medical Journal, 4(5578), 529-530.

Bauer, K. (1997). Foot- and-mouth disease as zoonosis. Archives of

Virology.Supplementum, 13, 95-97.

Berrios, E. P. (2007). Foot and mouth disease in human beings. A human case in Chile.

[Fiebre aftosa en seres humanos. Un caso en Chile] Revista Chilena De Infectologia

: Organo Oficial De La Sociedad Chilena De Infectologia, 24(2), 160-163.

Blackwell, J. H., & Hyde, J. L. (1976). Effect of heat on foot-and-mouth disease virus

(FMDV) in the components of milk from FMDV-infected cows. The Journal of

Hygiene, 77(1), 77-83.

Burrows, R. (1968). Excretion of foot and mouth disease virus prior to the development

of lesions. Veterinary Record, 82, 387.

Burrows, R., Mann, J. A., Greig, A., Chapman, W. G., & Goodridge, D. (1971). The

growth and persistence of foot-and-mouth disease virus in the bovine mammary

gland. The Journal of Hygiene, 69(2), 307-321.

Donaldson, A. I. (1997). Risks of spreading foot and mouth disease through milk and

dairy products. Revue Scientifique Et Technique (International Office of Epizootics),

16(1), 117-124.

Goff, H. D. (2007). Chapter 8: Dairy product processing equipment. In M. Kutz (Ed.),

Handbook of farm, dairy, and food machinery (pp. 193-214). Norwich, N.Y.,

U.S.A.: William Andrew Publishing.

Hyde, J. L., Blackwell, J. H., & Callis, J. J. (1975). Effect of pasteurization and

evaporation on foot-and-mouth disease virus in whole milk from infected cows.

Canadian Journal of Comparative Medicine. Revue Canadienne De Medecine

Comparee, 39(3), 305-309.

Hyslop, N. S. (1973). Transmission of the virus of foot and mouth disease between

animals and man. Bulletin of the World Health Organization, 49(6), 577-585.

26

Kahrs, R. F. (2001). Viral diseases of cattle (2nd ed.). Ames, Iowa: Iowa State University

Press.

Lopez-Sanchez, A., Guijarro Guijarro, B., & Hernandez Vallejo, G. (2003). Human

repercussions of foot and mouth disease and other similar viral diseases. Medicina

Oral : Organo Oficial De La Sociedad Espanola De Medicina Oral y De La

Academia Iberoamericana De Patologia y Medicina Bucal, 8(1), 26-32.

Mayor, S. (2001). UK investigates possible human cases of foot and mouth disease. BMJ

(Clinical Research Ed.), 322(7294), 1085.

Mort, M., Convery, I., Baxter, J., & Bailey, C. (2005). Psychosocial effects of the 2001

UK foot and mouth disease epidemic in a rural population: Qualitative diary based

study. BMJ (Clinical Research Ed.), 331(7527), 1234.

OIE - World Organisation for Animal Health. (2002). Foot and mouth

disease.http://www.oie.int/eng/maladies/fiches/a_A010.HTM

Prempeh, H., Smith, R., & Muller, B. (2001). Foot and mouth disease: The human

consequences. the health consequences are slight, the economic ones huge. BMJ

(Clinical Research Ed.), 322(7286), 565-566.

Ryan, E., Mackay, D., & Donaldson, A. (2008). Foot-and-mouth disease virus

concentrations in products of animal origin. Transboundary and Emerging Diseases,

55(2), 89-98.

Sellers, R. F. (1971). Quantitative aspects of the spread of foot and mouth disease.

Veterinary Bulletin, 41(6), 431-440.

Sutmoller, P., Barteling, S. S., Olascoaga, R. C., & Sumption, K. J. (2003). Control and

eradication of foot-and-mouth disease. Virus Research, 91(1), 101-144.

Terrestrial animal health code - 2007. Retrieved 6/10/2008, 2008, from

http://www.oie.int/eng/normes/mcode/en_chapitre_3.6.2.htm

The Food and Drug Administration, US Department of Health and Human Services,

Washington, DC. (2007). Pasteurized milk ordinance. 2007 revision

Tomasula, P. M., & Konstance, R. P. (2004). The survival of foot-and-mouth disease

virus in raw and pasteurized milk and milk products. Journal of Dairy Science,

87(4), 1115-1121.

Tomasula, P. M., Kozempel, M. F., Konstance, R. P., Gregg, D., Boettcher, S., Baxt, B.,

et al. (2007). Thermal inactivation of foot-and-mouth disease virus in milk using

high-temperature, short-time pasteurization. Journal of Dairy Science, 90(7), 3202-

3211.

27

U.S. Department of Agriculture (USDA)/ Animal and Plant Health Inspection Service

(APHIS). (2007). Foot and mouth disease factsheet. Unpublished manuscript.

Retrieved 5/14/2008, from

http://www.aphis.usda.gov/publications/animal_health/content/printable_version/fs_

foot_mouth_disease07.pdf

Ulcer, aphthous definition - medical dictionary definitions of popular medical terms

easily defined on MedTerms. Retrieved 6/13/2008, 2008, from

http://www.medterms.com/script/main/art.asp?articlekey=16043

Walker, J. S., de Leeuw, P. W., Callis, J. J., & van Bekkum, J. G. (1984). The thermal

death time curve for foot-and-mouth disease virus contained in primarily infected

milk. Journal of Biological Standardization, 12(2), 185-189.

28

Appendix A. Bibliography of Sources utilized for generation of Table 4 (Ryan et al.,

2008)

These articles may be of use in further review of FMDV

Bekkum, J. G. V., and P. W. D. Leeuw, 1978: Some Aspects of FMDV in Milk. 6th

International Congress Veterinary Science, La Plata, Argentina

Blackwell, J., 1976: Survival of foot-and-mouth disease virus in cheese. J. Dairy Sci. 59,

1574–1579.

Blackwell, J., 1978a: Persistence of foot-and-mouth disease virus in butter and butter oil.

J. Dairy Res. 45, 283–285.

Blackwell, J., 1978b: Potential transmission of foot-and-mouth disease in whey

constituents. J. Food Prot. 41, 631–633.

Cunliffe, H. R., and J. H. Blackwell, 1977: Survival of foot-and-mouth disease virus in

casein and sodium caseinate produced from the milk of infected cows. J. Food Prot. 40,

389–392.

Cunliffe, H. R., J. H. Blackwell, R. Dors, and J. S. Walker, 1979: Inactivation of

milkborne foot-and-mouth disease virus at ultra-high temperatures. J. Food Prot. 42,

135–137.

Donaldson, A. I., 1997: Risks of spreading foot and mouth disease through milk and

dairy products. Rev. Sci. Tech. 16, 117–124.

Hedger, R. S., and P. S. Dawson, 1970: Foot-and-mouth disease virus in milk: an

epidemiological study. Vet. Rec. 87, 186–188.

Hyde, J. L., J. H. Blackwell, and J. J. Callis, 1975: Effect of pasteurization and

evaporation on foot-and-mouth disease virus in whole milk from infected cows. Can. J.

Comp. Med. 39, 305–309.

Kihm, U., W. Bommeli, and N. Kurmann, 1979: Persistence of FMD virus in

Emmentaler cheese. Report of the Session of the Research Group of the Standing

Technical Committee of the European Commission for the Foot-and-Mouth Disease,

Lindholm, Denmark, 12–14 June 1979. FAO, Rome.

29

Appendix B: Stakeholder Information

Stakeholders:

This list of stakeholders represents the main groups involved in the questions

posed by DMI in relation to FMD. Recognition of the roles that the stakeholders play is

of paramount importance when developing materials that can be dispersed to various

audiences. Each stakeholder‟s relation to FMD prevention, control, and communication

will be identified and their relevance to the topic briefly discussed.

University of Minnesota: School of Public Health and College of Veterinary Medicine:

- Communicators of risks.

- Influence economic implications due to value of product:

Our perception of risk can influence how consumers view dairy

products due to our influence on public perception of risk.

- Dairy product processing methods development. Methods design and

improvement can take FMD control measures into account.

Dairy Industry Communicators:

- Communicators of risk.

- Inform public on standardized product – processing methods control and

regulations.

- Responsible for relaying information to consumers on dairy products and food

safety considerations.

Dairy Industry at all levels from farm to table:

- Evaluate and regulate product processing methods.

- Provide quality product to consumer.

- Economic implications due to value of product and loss of productivity.

- Psychosocial:

Farmers would be directly impacted if fear of FMD in milk caused a

decrease in milk value and resulted in economic hardship. Depopulation

and quarantine of herds in a crisis situation would have psychosocial

effects beyond just the loss of productivity.

Veterinarians:

- Economic implications due to value of product and loss of productivity.

- Can influence economic implications due to value of product:

Their perception of risk can influence how consumers view dairy

products due to their influence on public perception of risk.

- Communicators of risks.

- Ensure product processing methods are controlled.

- Responsible for relaying information to people regarding dairy products and

production. Veterinarians are often the first source of information related

to diseases such as FMD.

30

Milk Consumers:

- Influence the value of dairy products due to their perception of risk. Actions of

all of the stakeholders involved will in some way influence the decisions

of the milk consumer to continue or discontinue consumption.

- Need to be provided with safe, quality-assured product.

State Departments of Agriculture and USDA /APHIS:

- Communicators of risks.

- As representatives of the agricultural industry, they are responsible for relaying

information to consumers regarding dairy products.

- Product processing methods control and regulation.

- Can influence economic implications due to value of product:

Their perception of risk can influence the consumer‟s view of dairy

products due to their influence on public perception of risk.

- They are responsible for detection and control of disease outbreaks, and

managing a crisis situation. This division would coordinate local, State,

and Federal response and eradication efforts, coordinate interagency

planning, and implement national communication and information-sharing

strategies, as well as maintain contact with U.S. trading partners.

State Departments of Health and Human Physicians:

- Communicators of risks, especially in times of disease outbreaks and food safety

concerns.

- Can influence economic implications due to value of product:

Their perception of risk can influence the consumer‟s view of dairy

products due to their influence on public perception of risk.

Consumer Watchdog Groups / Non government organizations:

- Serve as unofficial communicators of risks.

- Can influence economic implications due to value of product:

Their perception of risk can influence the consumer‟s view of dairy

products due to their influence on public perception of risk.

Recognizing the Role of Stakeholders Involved:

Dairy industry communicators are responsible for relaying information to

consumers regarding pasteurized dairy products and reinforcing that FMD is an animal

disease and not a public health threat. Milk and other dairy products are still safe to

consume during an FMD outbreak. Persons in this field can have a positive economic

impact on the value of milk if information is properly dispersed.

The Dairy Industry at all levels, from farm to table, can also serve to maintain the

value of milk. Farm workers and managers are responsible for maintaining sanitary

milking conditions and bulk storage of the product. As the product is transferred into the

milk processing line, conditions specified by the PMO need to be followed and monitored

31

on a continuous basis to ensure for destruction of FMD and other pathogens. These

groups would be directly impacted if fear of FMD in milk caused a decrease in milk

value and resulted in economic hardship. Depopulation and quarantine of herds in a crisis

situation would have psychosocial effects beyond just the loss of productivity.

Veterinarians are viewed as an expert opinion to clients, media, and general

public audiences. They are responsible for relaying information to people regarding dairy

products and discussing that FMD is an animal disease and not a public health threat

when consuming pasteurized milk. Veterinarians not involved in agricultural venues

would need to be informed of the current findings in the scientific community regarding

FMD and pasteurized milk as a non-risk to humans. Persons in this field can also have a

positive economic impact on the value of milk if information is properly dispersed.

State Departments of Agriculture and USDA /APHIS represent the agricultural

industry. They are responsible for detection and control of disease outbreaks, and

managing a crisis situation. As mentioned earlier, this division would coordinate local,

state, and federal response and eradication efforts, coordinate interagency planning, and

implement national communication and information-sharing strategies, as well as

maintain contact with U.S. trading partners. Their actions can have a positive economic

impact on the value of milk if information is properly dispersed and they ensure that milk

is properly processed.

State Departments of Health and human physicians are viewed as expert opinion

to clients, media, and general public audiences. Persons in this field can have a positive

economic impact on the value of milk if information is properly dispersed. Depopulation

and quarantine of herds in a crisis situation would have psychosocial effects on their

patients beyond just the loss of productivity and planning to address this should be

considered.

The dairy product consumer is influenced by information from all of the

stakeholders mentioned in this review. By properly dispersing information about FMD,

all other stakeholders can ensure the consumer of the scientific community‟s findings

that, although humans have been documented as contracting FMD, the likelihood of

contracting the illness is very low and that pasteurization significantly decreases the

likelihood of infection to a point where FMD is not a public health threat.